#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_dictionary);
getWindow().setSoftInputMode(
WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
setupNavMenu();
}
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new A(), "A");
adapter.addFragment(new B(), "B");
adapter.addFragment(new C(), "C");
adapter.addFragment(new D(), "D");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
The problem is:
When I starts the activity, i get the first fragment's view(A), BUT the next fragment(B) loads without the view, so when I slide to the next view(B), i get the view that i'v been loaded at the previous fragment, so now It's load fragment C...
the problem is that fragment B's content depends on the input in fragment A (data saved is sharedpreferences) so I allways get the default value at fragment B because it was loaded in fragment A.
The bug works the same way when I'm in the fragment D, so when I'll slide left to fragment C, it will show fragment C AND loads fragment B also.
its not a bug its the default functionality of a viewpager. for each nth page (n-1)th and (n+1)th page loads automatically with the nth page. I don't think there is any straight forward way to achieve what you want.
The best way would be to use a custom onSwipeListener instead of ViewPager and load the fragment yourself..
But for ViewPager you can use a hack:
After saving data in fragment A,
viewPager.setAdapter(adapter);
which will reload all fragments.
Don't forget to first save the current pager position.
after reset, set pager position so you don't go back to the first position every time.
not good coding but it should work.
on your ViewPagerAdapter. override method : getItemPosition : return POSITION_NONE
Related
I am having trouble with below code, i have 5 tabs in my application and when i am trying to switch through them i just noticed that onCreateView is called multiple times. Now first i did saw multiple post about similar issue where multiple times onCreateView is called, but mine is lit bit different, in my application onCreateView is called based on number of tabs i am switching. For example if i am DOWNLOAD tab and i switch to FAVORITE, onCreateView will be called 3 times. If i do same action from settings it will be called 4 times. Same thing happens with CANDIDATE and other tab.
Similar Posts -
1 - OnCreateView called multiple times / Working with ActionBar and Fragments
2 - Android fragment OnCreateView called twice
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
private Boolean exit = false;
private static final int REQUEST = 112;
private Context mContext;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
TextView mTitle = (TextView) toolbar.findViewById(R.id.toolbar_title);
setSupportActionBar(toolbar);
mTitle.setText(toolbar.getTitle());
getSupportActionBar().setDisplayShowTitleEnabled(false);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
mContext = MainActivity.this;
setupTabIcons();
}
#Override
protected void onResume()
{
super.onResume();
}
private void setupTabIcons() {
tabLayout.getTabAt(0).setIcon(getResources().getDrawable(R.drawable.settings));
tabLayout.getTabAt(1).setIcon(getResources().getDrawable(R.drawable.download));
tabLayout.getTabAt(2).setIcon(getResources().getDrawable(R.drawable.register));
tabLayout.getTabAt(3).setIcon(getResources().getDrawable(R.drawable.profile));
tabLayout.getTabAt(4).setIcon(getResources().getDrawable(R.drawable.favwhite));
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new SettingsFragment(), getResources().getString(R.string.settings_tab));
adapter.addFragment(new DownloadFragment(), getResources().getString(R.string.download_tab));
adapter.addFragment(new RegisterFragment(), getResources().getString(R.string.register_tab));
adapter.addFragment(new ProfileFragment(), getResources().getString(R.string.profile_tab));
adapter.addFragment(new ProfileFragment(), getResources().getString(R.string.favorites_tab));
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(0);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
Update -
To add more when it is run 4 times the data on screen is 4 times which is duplicate.
Fragement Code -
public class RegisterFragment extends Fragment{
public RegisterFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_register, container, false);
}
#Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser) {
getFragmentManager().beginTransaction().detach(this).attach(this).commit();
}
}
}
By default view pager load the fragment in the following order.
Currently selected position fragment. Visible
Cache for the (selected position - 1) fragment, if any. Not visible
Cache for the (selected position + 1) fragment, if any. Not visible
Reason for this is, to make smooth animation from one fragment to another without lagging, view pager caches the previous and the next fragment. To confirm this log the position in the getItem() method in the view pager adapter.
As a result of above. When launching activity your viewpager is loading position 0 and 1. ie loading 2 fragment. There is no fragment in -1 position.
I'm developing an Android Application where I have a ViewPager in my MainActivity, consisting of 3 Fragments.
The Problem is as follows, when I swipe to the 3rd fragment, and get back to the 1st one, onCreateView of fragment 1 is called which is what I really want, however, If I swipped to the 2nd fragment only, and returned to the 1st one, onCreateView is not called!
I need to find a solution to this problem, I spent hours trying to find a solution but didn't know to solve it.
Here's the code related to the ViewPager in my MainActivity
private void setupViewPager(final ViewPager viewPager) {
final ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new voting(), "ONE");
adapter.addFrag(new dashboard(), "TWO");
adapter.addFrag(new chats(), "THREE");
myAdapter=adapter;
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(0);
}
private class ViewPagerAdapter extends FragmentStatePagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<Fragment>();
private final List<String> mFragmentTitleList = new ArrayList<String>();
private ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
Log.i("getItem","getItem");
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
private void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
//added newly
#Override
public int getItemPosition(Object object){
return PagerAdapter.POSITION_NONE;
}
#Override
public CharSequence getPageTitle(int position) {
return null;
}
}
This is intended behavior with a FragmentPagerAdapter. If the fragment was already created and is still in memory, it is just reattached to the ViewPager. Hence, the reason why onCreateView(...) isn't called a second time.
Implementation of PagerAdapter that represents each page as a Fragment that is persistently kept in the fragment manager as long as the user can return to the page.
You're using a FragmentStatePagerAdapter which is a subclass of FragmentPagerAdapter, so it inherits this behavior.
Generally, it's not a good idea to recreate a view on every page change, as that is expensive and can lead to non smooth scrolling. If you had some logic in onCreateView(...) that you want to run again on each fragment change, then I suggest looking into ViewPager.OnPageChangeListener interface.
I have an activity named: ShoppingListActivity in which i have added 3 fragments. For this example i will use only one fragment. In onCreate method i have declared a ViewPager that looks like this:
ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
and a setupViewPager(viewPager); method that looks like this:
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
Fragment shoppingListFragment = new ShoppingListFragment();
getSupportFragmentManager().beginTransaction().add(shoppingListFragment, "ShoppingListFragmentTag").commit();
adapter.addFragment(shoppingListFragment, "SHOPPING LIST");
viewPager.setAdapter(adapter);
}
My ViewPagerAdapter class lookslike this:
private class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> fragmentTitleList = new ArrayList<>();
ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public int getCount() {
return fragmentList.size();
}
void addFragment(Fragment fragment, String title) {
fragmentList.add(fragment);
fragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return fragmentTitleList.get(position);
}
}
My problem is when i go from ShoppingListActivity to another activity and than come back, my fragments are not refreshed. This is my code from onResume method in which i try to find the fragment to detach and attach the fragment like this:
FragmentManager fragmentManager = getSupportFragmentManager();
ShoppingListFragment shoppingListFragment = (ShoppingListFragment) fragmentManager.findFragmentByTag("ShoppingListFragmentTag");
fragmentManager.beginTransaction().detach(shoppingListFragment).attach(shoppingListFragment).commit();
The problem is that i get this error: java.lang.IllegalStateException: Can't change tag of fragment ShoppingListFragment{528673f4 #0 ShoppingListFragmentTag}: was ShoppingListFragmentTag now android:switcher:2131558559:0
How can i set the Tag correctly to the fragment?
Thanks in advance!
from the code what I understand is, There is a ViewPager implemented in ShoppingListActivity along with tabs.
In viewpager each fragment contains the list of something which come from server right? Now you want to refresh whole viewpager when user back from the ShoppingListInfoActivity right?
Do below changes in you ShoppinglistActivity.
1) Declare ViewPagerAdapter adapter; at class level global.
2)change private class ViewPagerAdapter extends FragmentPagerAdapter
replace FragmentPagerAdapter to FragmentStatePagerAdapter
3) change in onresume()
#Override
protected void onResume() {
super.onResume();
if(adapter!=null){
adapter.notifyDataSetChanged();
}
}
Here i am getting result like...
Activity start..
at at that time these two fragments calls
-> Fragment 1 load
-> Fragment 2 load in background
swapping right (means going from frag 1 to fragment 2)
at that time I am in fragment two and same time
-> Fragment 3 load in background
swapping in right (means going from Frag 2 to 3 then)
--> there is nothing issue.
HERE IS MY CODE
Main Activity
#Override
protected void onCreate(Bundle savedInstanceState) {
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new OneFragment(), "ONE");
adapter.addFragment(new TwoFragment(), "TWO");
adapter.addFragment(new ThreeFragment(), "THREE");
viewPager.setAdapter(adapter);
}
This is my adapter class
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
// add fragment
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
// for title
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
And there is 3 fragment right now there is nothing into that fragment .....
ViewPager setOffscreenPageLimit default is 1
Please view this link
Visit Documentation
Update
Please Override this method of fragment
#Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (isVisibleToUser) {
// load data here
}else{
// fragment is no longer visible
}
}
Use this tutorial..this may helps you
http://www.androidhive.info/2015/09/android-material-design-working-with-tabs/
you need not include this lines in your onCreate Method (Remove this lines)
viewPager.setCurrentItem(0);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
By default,Viewpager will set '0' for starting index..
Replace your code with this. This runs well on my app :
#Override
protected void onCreate(Bundle savedInstanceState) {
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
assert tabLayout != null;
tabLayout.setupWithViewPager(viewPager);
tabLayout.setSelected(true);
}
And no need to add viewPager.setCurrentItem(0);
Because by default ViewPager will be set to the Starting index of 0. As already told by Ajay Jayendran.
Hope this will works. (:
I have two fragments.
1) A fragment with just a TextView(OneFragment)
2) A fragment with a recycler view who's contents are being populated in the onCreateView() of the Fragment (Two Fragment)
In the Activity class I use a viewPager to control these fragments!!
However I'm faced with the problem.
The onCreateView() method of the TwoFragment is called when the activity is first loaded! When I go to the other fragments and return back to the Two Fragment the onCreateView() method is not called.
Instead of showing me a recyclerView it renders a blank screen ! However when I change my orientation of the device! The onCreateView() is called and and the list is populated!
I want it to show the TwoFragment while returning back to it.
However the OneFragment has no problems of this ! Any time I return to it, The normal big textView is shown!
Here is the Code for my ViewPager Adapter
class ViewPagerAdapter extends FragmentStatePagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getItemPosition(Object object){
// return PagerAdapter.POSITION_NONE;
Fragment f = (Fragment) object;
for(Fragment frag: mFragmentList){
return frag.getTagInt();
}
return FragmentStatePagerAdapter.POSITION_NONE;
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
public void clearAll(){
mFragmentList.clear();
mFragmentTitleList.clear();
notifyDataSetChanged();
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
And I set The ViewPager adapter like this :
private void setupViewPager(ViewPager viewPager,int choice) {
if(choice == 1){
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.clearAll();
adapter.addFragment(new OneFragment(), "One");
adapter.addFragment(new TwoFragment(), "Two");
viewPager.setAdapter(adapter);
}
else{
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.clearAll();
adapter.addFragment(new OneFragment(), "One");
adapter.addFragment(new OneFragment(), "Two");
viewPager.setAdapter(adapter);
}
}
and here's my previous getItemId()
#Override
public int getItemPosition(Object object){
// return PagerAdapter.POSITION_NONE;
Fragment f = (Fragment) object;
for(int i=0;i<getCount();i++){
Fragment fragment = getItem(i);
if(f.equals(fragment)){
return i;
}
}
return FragmentStatePagerAdapter.POSITION_NONE;
}
Any kind of help is Much Appreciated ! Cause I'm kinda stuck after going through the web and stackOverflow!!
You should not return POSITION_NONE in getItemPosition () for every request. POSITION_NONE means you're telling the pager adapter that this particular fragment is removed from the list and please modify the pages/fragments accordingly. When you return this, adapter will delete the fragment from its own private list of fragments. This is returned when you want to remove the fragment.
Send the position of the fragment using the indexof method of list interface.
See this post for more info.